Telephone system



March 17, 1925. v 1,529,$55

L. D. KELLOGG TELEPHONE SYSTEM Filed June 12. 1919 s Sheets-Sheet 1 O;Mv fiZZZzrneg JUL/F2770]? March 17, 1925.

5 1,529,655 L. D. KELLOGG TELEPHONE SYSTEM Filed June 12, 1919 3Sheets-Sheet 2 Jim/222701? LEPU ZZKEZZU y fifi rzzgg L. D. KELLOGGTELEPHONE SYSZPEM Mmh 17. 1925. 1,529,655

Filed June 12. 1919 3 Sheets-Sheet 3 g LerqylYKeZ/agy- N 5 j (1m;

' y CUP? tented Mar. 17, 1925.

UNITEDi sTAIEs LEROY D. KELLOGG, 0E DEERFIELD, ILnINoIs, ASsIeno'a TOKELLOGG swmnmm' 5 'AND SUPPLY COMPANY, or CHICAGO, ILLINOIS, Aoo-srormrron or ILL NOIS.

V TELEPHONE SYSTEM.

-Applieation filed June 12,

To all whom it may concern: H I I Be it known that I, LEROY D KELLQGG, acitizen of the United States of America, residing at Deerfield, countyof- Lake, and $tate of Illinois, have invented certain new and usefulImprovements in Telephone Systems, of'which the following is aspecifica- My invention relates to telephone systems of the two-wire ormetallic line type in which the directively controlled switches at theexchange are operated responsive to a series of; rapid interruptions ofthe subscribers line circuits, and an ob ectof my invention s to providea system as outllned having simplified andimproved circuit arrangements.a u

My system includes a line finder switch for use in a system of thecharacter, outlined above, and a feature of my invention resides in theprovision of a so-called positive drive circuit for the finder switch inboth its primary and secondary movements. A further feature ofmy'inventionresides in the provision of a so called positive drivecircuit for the master switch associated with the line finder switchesinmy system, A still further feature of my invention resides in thecircuit arrangement of my finder switch, which has a vertical, downwardprimary selecting movement, and a rotary, secondaryselecting-movement,and is advanced in a rotary direction beyondthe lastcontact in the bank level to 1 permit restoration of the finder switch.A still further feature of my invention is the provision of quick andslow-acting're' lays for use in my line finder, first selector andconnector switch circuits, the switch structures of which have switchshafts and wipers that are advanced downwardly ina vertical plane whenperforming a primary selecting movement, rotated ina horizontal planewhen performing a'seconclary movement and subsequently arerotated beyondthe last contact of the bank level to permit the switch shafts andwipers to be restored by'springtension to normal. 1 In the positivedrivecircuit, a motor magnet is controlled by a test relay which inturnis controlled by the motor magnet."

The novel features of my invention," through the provisionof which theabove- 1919. s ria naeoaaia V mentioned and other advantageous resultsare obtained, will be explained byreference to the accompanyingdrawings, in which Figure 1,, comprising,parts :1 2 andB, i1-

lustrates diagrammatically an automatic telephone system embodied inmyinvention;

V ;Referring.to the system illustrated in the accompanying drawings, thesystem there illustrated may be considered as a thousand line system.Assuming such to be the case, Ieach'subscri-bersline such as those ofSubstations A and E extends to the exchange and is, there provided withits individual passive contacts appearing with those of particularfirstselector, Such, as C, which is automatically brought under thecontrol of currents transmitted over the calling line by the operationsofthe line selector B, Responsive to currents transmitted over thecalling line, the first selector is operated to select the group ofconnectors desired, and

banks often connectors.

As above indicated, lineselector Bh'by ers lines. The contacts oftheselines are preferably arranged inten groups of ten o contact setseach, the motion of the-wipers j of the finder switchj B being first ina prininety-nine other lines in the contact'banks v of ten lineselectors such as B. 4 Each line. selector has permanent; connectionwith a means of 'itsJwipers-has access-to, one hundred sets offmultlplecontacts forming ter- 'minals of aigroup of one hundred subscribmarydirectionin one plane to select 'agroup of contacts and theninrasecondary direction in another plane to select the I calling. lineof the group. Each group often lines, therefore, has'acoimnon orgroupcontact 41, controllablebya relay 8; Wiper22engagesthegroup contact 41.Wiper 22 controls the primary group ofnthe switch B.

When thewiper 22. reachesagroup; contact belonging to a group of linesamong which a calling line is included, the primary move- .ment of .thewiper is arrested andwipers 23, .24 and 25 then initiate the secondarymovement to select the contacts of a calling line, wiper 22 remainingquiescent at this time and not partaking ot the secondary movement'. Asbefore "stated,each group-of one hundred calling lines has associatedwith 11;

ies se scto s 31B Se: t at the s asts Q11- h; line-end th ;srq r. n a41, at ea groupie mutipled ten times, once to each such line selectorbank. v,

When the calling subscriber removes his "receiver he causes alineselector start operation to seek out his line, and thereby" cennect"afirsjt 'selecter with his line.

This "is efie'cted through the agenc at the master switch 'X callingline is enabledto transmit cement viafth'e switchcontacts 5"o'fits linerelay LR. The said master sweet, when operated at the initiation of thecall, causes an idle lineselector to start its operation. The line.selector-then reacts. uponv the master switch in such manner that itswipers. L2 and 13 move away fromvswitch. contacts of the line selectorwhich they start, and then lieepup an; independent progressive movementviaterminals of busy line selectors until they reach terminals oi anidle one,

I when the said wiperscome-to rest. The detailed operationof thedifferent parts one with another will be best: understood through thenarrative of operation;

The substation A comprises the usual switch hook and" substationequipment and includes acalling deviceCD. The substation is connected bymeans of the two line limbsj shown to rela mechanism at the exchange.The relay mechanism;- includes the line relay and cut-offrelay CO Themaster switch X includes a starting relay 7 a slow'rel'ay 1 8, a testrelay 37 and a 'motor'niagnet 36. Motor niagnet 36 is adapted throughthe medium of'ratchet and pawl mechanism to rotate the switch shaft andwipers 12 and 1-3 over the bank contacts 1 5 and 34c; The wipers of'the. master switch are so arranged that when one arm on the wipersvmoves rirom the last bank. contacts, another arm thereof engages: thefirst hank contacts of the bank oii' contac ts.

The circuits shown f-orft'he finder switch .13, first selector andconnector D are To energizerelay '7, each energized byimpulses from thecalling tacts of the calling subscribers line. A switching relay 33 isalso provided, which when energized; extends the connection ofthecalling substation A to the idle first selector G. Primary andsecondaryoff-nor 9I. a0ts P N a d ON, esp i e y,

arelp-rovided, The saidprimar oil'g-nor'm'al' contacts PON assume theiralternate position, upon the first step of the wipers in a primarydirection, and the secondary oifnormal COntactS' SQN assume theiralternate position upo'nthe first step of the wipers in asecondary'directio'n; it pair of slow relays PSR an'd SSR are alsoprovided] The first selector comprises an impulse relay- IR, which'rel'ay is energized and dedevice GD at the calling substation A. Thede-energiz'ations o't-the' relay l ltbring about the actuation of theprimary magnet PM to step the first selector switch wiper-s74,

'75 and 76 in 'a'primary' direct-ion'to a certaingroup of contacts. Asecondary magnet is provided i'or said selectorwhich automatically stepsthe said wipers in a secondary direction over the contacts 90, 9'1 and-92- in the selected group to seek out an idle set of contacts leading tothe connector D; A switching relay is also provided, which whenenergized; extends connection of the calling substation A; to the idleconnector D. Primary and secondaryofE-normal contacts and. SON,respectively, are provided and are controlled in substantiall yv thesame manner as are the contact springs PQN and SON of the finder switch13. A pair of slow relays 57 and 58 are also provided:

The connector switch D is provided with an impulse relay IR", responsiveto; the impulses of the'callingdevice CD at the calling substation A,which relay IR brings about the actuation of: the primary magnet Pl\ 2to step tllBvGOllIlGCtQl switch wipers 110, 111 and 112 in a primarydirection to an: elected group of" contacts containing contacts of thecalled line E. A switching relay SW is provided which energizes upon.the termination of the first set of impulses and connects the secondarymagnet 8M in. circuit with the impulse relay TR to be actuated by theenergi-Zation and de-energization thereof to step the connector switchwipers over the bank contacts in the selected group to seek the contactsof the called line A slow-acting relay 100 is provided and a slow-actingswitch relay 107. A test relay TR is also provided, which is actu-v atedto testthe' busy or idle condition of the called subscribers line, thesaid 1 test relay TR operating to connect busy back apparatus BB to thecalling subscribers line to notify the calling subscriber of the busycondition of the called line. A ringing control relay 133 is providedfor intermittently I applying ringing 'c'u'rrent to the calledsubscribers line from the ringing generator- G. A back bridge orsupervisory relay 141 is also provided, whichoperates'upon the responseof the called subscriber and :controls disconnection or prevents'further applicae tions of'ringing current to the called subscriberslineQ- Primary'and secondary -ottnormal contacts PON and SON xareprovided and assume their alternate positions upon the' primary andsecondary .Imovements of the switch shaft and wipers.

To the right of: Fig. 1, Part 3, I show a called substation E similar tosubstation A, substation E being connected'to line relay mechanism' K atthe exchange, similar to line mechanism K. I

Having described in general the structure of the switches and apparatus,I Willnow explain more in detail the operations.

Assuming that subscriber A is to befconnected with subscriber E, whosetelephone number will be assumed to be 456,,subscriber A first removeshis receiver, thereby completing a conductive bridge of his lineconductors by the usual elevation of the switch lever. Line relay LR isenergized by current from battery therethrough, its break-betore-makecontact 2, normal contact 3 of relay GO, over one side of the linethrough the substation and back over-the other side of the line andthrough normal contact 4 of relay CO; Relay LR upon energizing,placesground through its alternate contact; 5 on the private bankcontacts of the connector switches that have access to substation A.Another result of the energization of relay LR is that itcloses alocking circuit for itself traced from battery through its winding, itsalternate contact 5, contact 6 of relay CO, and the winding of relay 7of the master switch X to ground, independent of its'initial energizingcircuit. A further result due tofthe energization of the relayLR is thata circuit is closed for sub-group relay 8 extend; ing from batterythrough thewindingi 01 said relay, alternate contact 9 of relay LR,normal contact 10 of relay CO to ground. Relay 8 attracts its armatureto remove ground from the multiple group cont acts 11 of the lineselectorsthat have access to the calling subscribers line.

Returning to the operation of relay 7 "oft the master switch X, thisrelay upon energizing closes a circuit through the primary test relay ofan idle finder switch (inthis instance finder switch B), with'which thewipers 12 and 13 of the-masterswitchX-are in engagement. This circuitmay be traced "from battery through the winding of relay PTR, normalcontact 14 of contactsPON, master switch bank contact lo, wiper 120fthe'master switch X, alternatecontact16 0f relay 7, and normal contact17 of relay 18 through, the winding of magnet, I PM and the to ground.The relayPTR upon 'energimi ing closes a circuiththrough the primarywinding of relay PSR to ground at alteia'v nate contact 19 of relayPTRRelay'PSR' energizing prepares a :circuitior the slowacting relay 18 "ofthe master switch ,X

which is, closed as soon as the wipers of the finder switch are moved;from normal and the oil normal contact 21 closed. The mag netPMenergizing causes the switch, wiper v22 tov take one step in a primarydirection,

moving said wlperinto engagement with the first group contact 41. Theshiftingof-the ofi? normal contact 14 to its alternate posi tlOIl' opensthe original energizing-circuit for relay PTR and'the shifting of ofinormal contact 21 to ;its alternate position closes an r energizingcircuit for-relay 26of the finder" switch B and for relay 1.8 of the*master switch. Xi; Thai-circuit for relay 26 extends frombatterythrough the winding-of said relay 26, alternate contact 27 ofrelay PSR and alternate contact 21=to ground, and'the' circuit for relay18 extends from battery through the. winding of Saidrelay 18,alternatecontact27of; relay PSR and alternate contact 121 to ground: Theenergization st relay 180i the master switch X opens the startingcircuit 3,0 at contact 17. Afurther result, due to the shifting otftheofi' normal contact21, lS'QlihQYClOSlIig of a'circuit for relay 37ofthelmast eriswitch X, which circuit extends from battery throughthewinding of said relay,.normal contact 35 ofrela'y 36, wiper'i-13-andits engaged bank contact 34 to ground at alternate contact 21. Relay Y37 ofjthe master switch upon energizmg closes a circuit throughthestepping magnet 3601 the master switch extending from battery,through the winding of said magnet 36, alternate contact 38 of relay 37.to

ground. The magnet 36 upon. "energizing moves the wipers12and 13 intoconnection with the next set of bank contacts. If these contacts lead toa busy'finderswitchiB,the i engaged bank contact "34; will be found tohave a busy potential upon it. The energization ofthemagnet 36 offthemaster the bank contact 34 and wiper 13,,normal contact 35of relay 36.andthe' winding of relay137 ,to battery. Relay 37 {energizing againcauses a circuitfto be closed for the stepping-magnet36of the masterswitchyX.

The magnet 36 and the relay 37 arethus ineludedin ,a'vibratory circuit.arrangement and they operate alternatelyto, cause 1 loelmoved :intoengagementwithsa seta'ot' con tact'sleading toan idle: finderz switch".The

relayr1'8 has remained el'iergized during. this time to preventthewiper. 12 from applying ground to the bank contact 15' withwhichwiper12has moredover. i I

'Returning now to the operation of) the finder switch B, the' firstste'p thereof 'opens the circuit: ofrelay P-TR- at' contact 14 0i thePON springs. The de-ener-gization of PTR causes the Yde-energiz'ationor: the primary magnet The 'defenergizationfof magnet-PM again closes. acircuit for the primary test -relay PTR"extending from-hate tery throughthe winding of said relay, normallrontact 40 of magnet/5PM, contact 65of contacts! SON, jwiper' 2'2 andthje, engaged group bankfcontact 411110ground; Relay; PTR"'energi'zin-g, over this-- circuit again closes acircuit for relay P SR'ai-id1'magnct PM; The magnet PM again energizingsteps. the wiper 22 into engagementfwith.

the next group contactf41 and-1' opens the energizing circuit ofrelayP'lR'. The relay PTR and magnet PM will thus operatein a see-saw mannerto movethe Wiper 22 into enga ement with the group contact-41 associatecwith the group or level 'of contacts in which the calling subscribers'lineA -Q appears. The finder switch, wiper" 22'" haying 5 been movedinto engagementxwith' the group contact from which the relay 8" hasremoved ground, thev relay PTR" is permitted; to remain in;v itsde-energized position, thereby causing the SlOW*2IQt1I1g relay. P'SR"to' de: energize, Relay PS'R has remained-energazed during the entire?time that the relay P TR and magnet PMhave been co-operat ing to m'ovethe wiper 22-into engagement with the group contactgof the groupoffcontacts that contain the calling; suhscrihers line.v Relay PSR';de-energizing; removes ground-from relay 18; OlFmaSter switch X, andfrom relay 26 of'the finder-switchB, buththese relays dolnotide-energi'ze atthis timevasa substitute ground-"has been supplied forthese relays" through contact 32 of relay 33'. Relay PSRd'eenergizingagain closes its normal contact thereby clo singna circuit for secondarytest relay STR"e x'- tending from battery, through the-winding of saidrelay, normal contact 43 ofsecondary ofi normal contacts SON, alternatecontact 44 of-relay 26' and normal contact QfTy-Of relay PSR to groundat contact 21; The relay STR energizing, closesa-circuit for secondaryma "net SM'and secondary-switching relay SgR-extendingfrom; Batterythrough the windings of'said magnet and relay in series to alternatecontact 45 of relay STR. Magnet upon energizing,- moves the switch shaftwipers23; 24 and 25'*0ne1 step in, asecondary direction: into 1engagement "With the first set of bank cone.

tacts int the. seleetedrgroup; of; contacts and also moves. secondary.-ofi normal contacts 43 and izto theiralternate positions; The

opening of contact v 43 5 opens f the original inal 5, nergizing of linerelay it will he noted. that by the shifting of contact 9 of this relayto its-alternate position, infren'ioves ground from private contact 500f the finder switch bank contact's in: the level in whi'ch the calling.subscribefls lineappears. The engagement of 'wjiper 25With the firstbankwcontact, which inthis instance is ground, closes a circuit forrelay STR over the path just trac'ed'-= thereby causing the energizationof. relay; STR. Relay uponenergizing again closes a circuit for relaySSH and magnet SM; The magnet SM upon energizing causes the switch shaftwipers: to be moved into: engagement'with the second set of bankrcontact's and opens the energizin i circuitof relay- STRatits contact47-. l he relay. STRI- thus'wde-energi-zes and opensthe circuit. ofmagnet-SM;

The relayS TR' and; magnet-SM co-operate in this see-saw manner tomovethe switch shait wipers 23-, 24- and 125'l11tQ engagement with theset of' bank contacts connected to the calling subscribers' line. Thewipers 23, v

mal contact 51'0frelay SSR', alternate contactfi43 of the secondaryoffnormal" springs,

alternate contact 44 of relay 26 and normal cont'act'q27of-relay- PSR toground at-contact-2 1; Relay 33 upon energizing connects theheavilymarked talking conductors through fromv the finder'switclr to: theimpulse relay IR of first selector C, 0pens the test circuit ,of relay;*STR and also opens thecdocking circuit of relay '26,; The connectiomof? the; impulse relay IR, through to1thez calling-line causes the;energization; of

relay GO oftt'he suhscribers line equipment over a circuit extendingfrom "battery through the; winding of said, relay; CO, its normalcontaetl'l5l wiperv24', alternate contact" 52': of relay 33,, normalcontact 54 of relay. 55,, and? the upper winding ofv relay- IR to:groundr, Relaysi IR and CO1 energize 'oyen'this circuit; Relay; GO:energiz;

ing closes a locking circuitfor itself extending from battery throughits own winding,

its alternate contact 151, private wiper 25,

contact 48 ofrelay 26 (relay 26 now being in die-energized position)alternate contact 59 of relay 57, andalternate contact 60 of relay 58 toground. (Relays 57 and 58 having been energized when impulse relay IRenergized.) Further results, due to the energization of relayCO, are theconnecting of the calling line through'to the impulse relay IR, theopening of the locking circuit of relay LR, and the removing of groundfrom the calling subscrlbers line. The relay LR de-energizing permitsgroup relay 8 and starting relay 7 to return to their normal positions.Impulse relay IR is now held energized over the two sides of the callingsubscribers line in series over a circuit extendingfrom battery throughthe lower winding of said. relay IR, normal contact 62 of relay 55,alternate contact-.146

of relay 33, wiper 230i the finder switch B, out-over the calling lineand, through the calling substation back through alternate contact 3 ofrelay CO, wiper 24,,alter nate contact 52 of relay 33 and normal contact54 of relay 55 to the upper winding of relay IR and through its windingto ground. 7 i I.

The-calling subscribers line having been connected to a first selectorswitch C, the subscriber A now actuates the calling device ,CD to sendthree impulses of current over i the line, which impulses bring aboutthree rapid de-energizations and energizations 0f the impulse relay IR.The primary magnet PM energizes and de-energizes' three times due to theclosing and openingv of. contact 73 of relay IR which magnet oper-.

ates to step the wipers 74,. 75 and76 of the first selector in aprimarydirection to the third group of contacts, thus selecting the threehundredths group of connectors.

'. The circuit for the primary magnet extends from battery through thewinding of slowactingrelay 58, the winding of magnet PM,

normal contact 77 of off-normal contacts SON, contact 78 of relay 58,contact 79 of relay 57 and contact 73 to ground. The relay 58 wasoriginally energized through contact 80 of springs PON, but the originalcircuit for relay 58 is opened at the instant that the switch shaft ismoved from normal position and the contacts 80 operated. Con

, tact8l of the primary ofi normal springs moving to its alternateposition; connects ground to thetrunk release conductor 82; to maintainthe relay 33 of the finder'switch B in its energized position afterrelay 58 is de-energized and opens its alternate contact 60. After thelast impulse of the series of three impulses, relay 58 de energizes andcloses a circuit for test relay TRovcra path extending from batterythrough the winding ofsaid relay, contact 83,contactl8e= of relay 55,contact 86 of magnet sM.,;o g tact 87 of springs SON, contact 600irelay,

58, contact'59 ofjrelay 57; and alternatef contact 81019 springs PON toground; Test relay TR'energizing closes a circuit through secondarymagnet SM extendingfrom bate;

tery-through the winding of said ;m'agnet* and through alternate contact89 of. relay TR to ground. Secondary magnet SM energizing steps theswitch shaft anol' wipers one step in a rotary or'secondary direction toengage the first set of contacts90, 91 and 92, and the opening of normalcontact 86 of magnet SM causes the relay TR to de-,

energize. The first step of the'fswitch .shai't in a rotary directionfrom normal causes 1 J the secondary ofl normal contacts SON to be movedto their alternate position; The relay TR tie-energizing opens thecircuit of secondary magnet SM and permits itz to de-energize. Themagnet SM upon deenergizing connects the test relay .TR to the privatewiper 74.,of the selector switch C, andshou'ld the privatewiper engageacontact leading to a busy connector, a cirf cult is established forrelay TR extending from battery through the winding of. saidrelay,'-oontact 83, contact84, of relay-3'55,

contact 86 of magnet .SM, contact 93 of relay 57, contact 94 of relayv58 to the private wiper 74 (thefirelay "58 fagain' energizing" I whensecondary. magnet- SM, is energized). The relay TR energlz ng over th1scircuit again closesa circuit :for magnet SM and magnet SM in turncloses and opens the circuit ofrelayTR- The magnet SM and relay TRcontinueto operate until private wiper 74 engages a contact leading toanidle connector switch atwhichtlme the relay from battery through thewinding of said relay, secondary ofl' normal contact 87, normal contact60 ofjrelay 58, alternate contact 59 of'relay 57 and alternate contactSIl'lQf springsPON'; Relay 55 upon energizing disconnects the impulserelay IR fromthe subscribers line and" connects the sub-Q scribers linethrough to the impulse relay to the private wiper 7 4. .The connectingof the subscribers line through to .theimpulse relay IR of the:connector switch, causes this relayto ,be energized over the two'sidesvIR, of the connector switch D, andxat the I same time closes 'a lockingcircuit foritself of the calling subscrlbers" line iiiseries, and

the. energization; thereof closes a, circuit from attery throughlt e'w'inding' of sai throu h ,slow-a'ctmg ma netlOO, extending relay and:alternate wontact l or'of relay 1R to-fgro'und. 13912 1 100 energizingconnects gmu'nd to private, conductor 102 thereby maintaining relay 61.selector-*0 in an energized. position over a path extending from batterythrough "the Winding of "said relay 55, its alternate contact 103,Wiper- 74 and *bank' contact '92, conductor 102,= contact 1050f springsPON and *contact 106 of relay 100 to ground,

v 1 Returning to the first selector switch "G, the de-energi zing ofrelay IR "permits the slow-acting relay 57 to de energize and return :toits :normal position, The selector switch C is now held in -its ofinormal oradvanced position by the energization of relay 55. Theapparatus isnow in condition for the subscriber to send the secondseriesof impulses constituting 1 the second "digit of the callingnumber.

The calling subscriberoperates his calling 'deviceGD as-abovementimied,therebycau's ing five "de-ene'r-gizationsand ene'rgi-Zations ofm'elayliR. RelayIR upon its firs't oleenergization' ,cl-oses I a circuitthrough prinia fry ma net PM and slow-acting relay 107 in: series over acircuit extending -"l*"ro1n battery through the win'dingof said magnet,contact 108 ofrelay SW, contact 10-9 ofrrel'ay 100,' 'thr0u'ghtheWinding (if relay I07 and normal contact 101 of relay *"I'R to ground.Primary magnet PM operates to step the sWitchWipers 110, 11 1and 1l2fivesteps in a primary clire'ctionto the fifth level o'r'group of bankcontacts in which is situated the line Of'the calling subscriber,The'first "move ment of the=s-Witchshaftifrom normal ermits theprim'a'ryoii normal springs P N to 1110veto*their alternate position.After the last impulse ofthe series has been sent the slow-acting relay107 (lo-energizes and returns to its normal position *the'reby closing acircuit for switching-relay SlV'over'a circuit extendingfroni batterythrough the Winding of relay SWV, its contact 114, con tact 115 ofsecondary on normal springs SON, contaet "116 of relay 107 and contact117 ofsprings PON to ground.

' tact 10s of-switch relay SW alternate tom di -relay 07 andaiorma1contact: iols of relay 1'3"12 round. M gnet *SM o eraesi1to stepswitch-wipers 1 10, lll' and 112 in-"a sertondary direction into-=engagement -Wlllll the bank coi'i tactsof the walled 5 subscribers 1ine. The swi-t'ch sh a'ft moving -in asecondary direction operates thesecondaryolf -'-norina1 contacts EG-N lrfter "the last im ulse of theseries has'been trafismittei-Telay107 r'eturns to' 110 Pm a1 positionand f closes an- :ene'rgiZin-g circui t for test relay BR over a==pathxtenaing from .batrery through the winding of relay TR, alternatecontact 1=23fof relay SWV, n01'n'1 al contact 1'24 of relay 107, contact125 of 'spi-ings -SON ,--and to grouncl' -at alternate contact 101 ofrelay IR. Relay TR upon energizing opens 1 the i e ergizin circuit-offrel-ayfSl V'at its contact 121,'th'ei-'eby p'errnitti'ng 5 the "same totle' ener-gize. A further result, due to -t-l1e ienergization of relayTB, is that it connects "itself through itjs altern-ate contact 122*tothe rivateyvipei- 1 10 and *ift'he eontaet e axgefl by 'the Wiper 110 bebusy, the, private 'cont-aot 129 of the called line will begrotihded;thus'dlosing a locking cir'cuit for the said relay TR throughthe private-wiper.

UaZZed Zine idle.

Assuming that the called line is idle, private contact 129 o'f-"the'oalledi linewill "be fr'eeo'f round a nd the r'elay TR *Wilhnotreinainfenergize'd, but will de energi'ze. "The relay dc-energizingcauses the: "ene'r-giz'a-i tion I of :relay @1 28 by current frornbattei y, through the Windin g O9 'o'f the *ap'pafratus K individual--totl-ie cal-led subso'riber sline, contact 5 of HER, bank contact 129 andWiper 110,"normaLcontact 122 of relay 1 R, normal contact 18O-'of relay-S'VV, and the t wo Win-"dingsof relay 128 in'series and Contactgiz'aftion of rel a'y I28; 1 is "the connect-ion of generator 6 throughcontact 137 61 relay 135. and contact 13 8 er -relay 128 to baek lay12S*to hack-"contaet 1 40 "of relay 133. The -relay fdue totheinterrupter'iliis oper ate d intermittently to-conriet ringing current-frorn generator G *tln-o ugh the 4 line Wvipe'rs" 11*1 anti 112toi-fihe "called siibs'cribers line.

Revertin forf fthe momentto ""the operatio'n "rift-he cut'ofi'fl'elay GGof the ixidiyid- Contact reeofq-elayy-rseanu the connecting v of."gro'und 'YIEI'OHI alternate"contact-127ml reing of said relay, itscontact 142, and conual subscribers mechanism this. .relay operatlngdisconnects the line relay LB from the called subscribers line, therebyremoving substation control of the. line mechanism K from the calledsubscriber.

The called subscriber at the substation E is thus intermittently rung,and when the called subscriber answers and the relay 133i tact 143 ofrelay 141 to ground. A further result, due tothe energization of relay141 is the placing of ground through its alternate contact 1455, uponconductor 146. The

relay 135 energizing closes a locking circuit for itself through itslocking contact 147 to ground at contact 117 of springs PON anddisconnects the interrupter I from the relay 133, but locks the relay133 :to' groundthrough it's alternate contact '134. This locking circuitfor relay 133 may be traced from'battery through the winding of said Ito relay 133, alternate contact 132 ofrelay 128, alternate contact 134of relay 135 andcontact 117 of springstPON to ground. A further result,due to the energization of relay 135 is the disconnection of thegenerator G from the called subscribers' line.

The subscribers are now in conversational circuit, and the talkingcircuit may be traced over the heavily marked conductors, said circuitincluding the condensers K and K Release, I

Assuming that the subscriber at the calling substation 'A' is the firstto replace his receiver, the resulting de-energization of the impulserelay IR removes ground, from the trunk release conductor 102, therebyopening the holding circuit of relay of the first selector C. Relay'55'of the first selector C de-energizing closesanenergizing circuit fortest'magnet TR over'a path extending from battery through the :windingof said magnet TR, contact 83, normal contact 84 of relay 55, contact86, of magnet SM, normal contact 93 of relay 57 and alternate contact 81of the springs PON' to ground. The relay TR energizing, closes a circuitfor secondary magnet SM The relay PR and secondary magnet SMf are thusalternatelyenergized and de-energized (as before described), and thesecondary magnet SM steps the wipers 74, 7 5 and 76 past-the lastcontact ofthefrow or level of bank contacts, from which point the wipersare restored to normal by springv tension.

The secondary ofi-norm alhcontacts SON and the primary off-normalcontacts'PON are restored to normal and the opening of, alternatecontact ,81 ofthe. primary off- 1 normal contacts PON opens the energiZing circuit of the holding relayq33 ,ofthe finder switch B. Therel'ayl33 restoring,

closes a circuit for secondary testrelay STR 1 over a path extendingfrom battery, through the winding of said relay, contact 46 of relay 33,contact 47 of magnetSM, cont-act,

44 of relay 26, contact 27 of-relay PSR, and

primary off-normal contact 21 ,to-ground.

Relay STR energizing closesa. circuit for secondary magnet S M and therelayv STR and the secondary magnet SM alternately energize andde-energize as before described. The secondary magnet SM steps thewipers 22, 23 and 24 beyond the last contact of the row orlevel of bankcontacts from ;which point the wipers are restored to normal by springtension. r a

Secondary off-normal contacts SON and the primaryofltnormal contacts PONare restored to normal by the return of the switch shaft-to normal. Theremoval, of the ground from the trunk release conductor 102' permits thecut-.ofi' relay C0 of the call ing subscribers relay-mechanism Ktorrestoretonormal. I L v ,The subscriber E restoring his receiver uponthe switchhook interrupts the circuit of relay 141 at the switchcontacts, causing]- the said relay to de-energize. Relay ,141 'de-,

energizing and openingits contact 145, re. p moves ground, from the slowacting relay f 10 5 100. Slow-acting relay 100 dc-energizing closes acircuit for the secondary magnet SM, traced from battery, through saidmagnet SM contact160iof relay 100, and

contact 161' of springs PON tothe,inter rupter-I .The secondary magnetSM Jthus' steps the wipers 1'10, 111and 112 beyon d'the last set, ofcontacts in the group. j The wipers then'restore to normal ,by springtensions The restoring of the switch, shaft operates to restore theprimary ofi-normal contactsPON? and the secondary ofilnormal contactsSON These contacts restoring permit'thede-energization of the other relays of the'connector D, thereby returning the apparatus to normal foruse" in other connections. ITheremoval of ground from; bankcontact 129permits cut-oft relay-CO f restore to normal.

I Assuming now 1 that the subscriber at called substationE was firsttoreplace his of the called ,subscribers mechanismK .to

receiver upon the switch hook, the opening of the switch hook contactsat the substation E brings about the de-energization of the re lay 141;Nothing elsehappens at this'time as the rrelay IR is stillmaintained'energized over the line of the calling substation A. Thecalling subscriber at the substation I A replacing his-receiiierinterrupts the circuit of impulserelay IR at switchhook'contacts.

The de-energization o f relay IR opens thecircuit, of slow-acting relay100, causing the said relay to de'energize as hereinbefore'described.The slow-acting relay 100 deenrgizing causes the restoration of theswitch "D, as hereinbefore described. A further result-flue to the deenergi zation of relay IR is the removal of ground from trunk releaseconductor 102, permitting the restoration of switches C and B and'therelease mechanism *K otth'e calling subscriberfs, line as abovementioned.

Should the'subscriber at the called substation fail to replace hisreceiver, he permits a continued fenergization ot the relay I41, thusholding the contact ot thisrelay in its alternate position therebymaintairring slow-a'cting relay 100 in its 'ene'rgized position. Whenthe calling 'subs'criber replaces his receiver, the de-energi'zation ofrelay IR" reiiioves ground from'trunk release conductor 102 to'permit-the switches B and O to restore. A further *result due to thede-eneigization of relay [R is the 010sing o if anene'rgi zing" circuitfor slow-acting relay 1 67. This relay is'slowtoe'nergi'ze and permitsthe switches 13' and C to "restore to normal before it places a groundupon-trunk above, up to and'including'the time the rel'a'v TR"momentarlly energizes. The i'llne being busy, the private contact 129fhas a busy potential connected'to it, thereby causing a locking circuitto be'cl'o'sed for thetest relay-TR, traced from battery, through thewinding of said relay, its alternate Contact 122, and the privatew'iper110 to ground. Alternate contact 170 remains closed and connects busysignal apparatus 'BB to the callinglineto'transmitabusy signal tothecalling substation thus notifying the calling subscriber of the "busycondition of the called line.

The calling subscriber replacing his receiverdrops backthesline relay:IR .of the connector switch'lD and releases-the 'connec tion as'hereinbefore described.

'While I have shown a'sy'stem ot 1 ,000*line capacity, it is to "beunderstood .1 by inserting second selectors, the system may be increased{to a 10,000 line systeimetc.

While I have described my, invention optem, 'Ido 'not Wish to belimited-t0 this exact disclosure as my invention may be applied toothersystems Without departing from the spirit of the invention, andLtherefor'e, do not wishto be limited to this exact disclosure but aimto cover all such changes and modifications as come within the spiritand scope of the appended claims.

WhatrI claim as new and desire 'to secure by UnitedStates Letters Patentis:

1. A telephone system including :a' twoniotion subscriber-controlled"automatic side- SW-ltChlBSS switch, a relay and. a driving magnetadapted to operate alternately "for controlling one of said motions, anda second relay and driving magnet for-.controlling the other of said:motion, 'a' positive drive circuit arran-gement forssaid first relayand driving magnet, said circuit atrangement ineludin g'a' contactro'fsaid relay and a .contact'ofsaidmagne't, and a positive drive circuitarrangement for said .second relay and driving :magnet,-said circuitarrangementincluding a "contact. of said eratingin connection witha-well-lmown .sys-

second relay "and 'a'conta'ct of said second driving magnet. s

2. A telephone system including a Eplurality of automatic switches andtelephone lines, a rotary 'non-restoringimaster switch for controllingsaid automatic switches, motor magnet vand a relay forssa'id masterswitch eonnected in a positivevdrive' circuit arrangement, ='and."arelayrassociated with said ;autoinatic-iswitch 'for co'ntrolling thestarting ofw'the said positive" drive circuit arrangement "of-the relayand magnet- 20f said inaster switch, said last relay also adapted tooperate said automaticr'switch to select a "group of said itBlQPllOIiG(lines.

3. A telephone system including an automatic side-switchlesssivitchprovided with a switch shaft and wipers having motion in one plane toselectzgroups iof dines and motion in another plane to select a .line inthe I group, a =.relay and a magnet =-adapted to energize andde-energize falter'nately a plurality of times for controlling saidfirst motion, said relay and magnet being connected-in a positive drivecircuit arrange ment, automatic restoring means for said switch,,and asecond 'relay'eand magnet connected in a positive, drive f'circuitarrangement for controlling said second motion, said second relay, andmagnet operable through a positive drive operation itor permitting theoperation of i said automatic Krestoring -means. r

4:. A "telephone system vincluding {a subscriber-cont'rolled automaticSide sw-itchles's switch {provided with *a c switch shaftand to select aline in the group, a relay and a magnet controlling said second motion,a

circuit for said relay controlled by said magnet, a circuit for saidmagnet controlled by sald relay,sa1d relay andsaid magnet adapted tooperate alternately a number of times for advancing sald switch in oneplane switchhavmgunotion in Oneplane' w se ofsaid motions, and restoringmeans includ ing said relay and magnetfor restoring said automaticsWitchto no-rmal'said last relay and magnet being ma positlvedrivecircuit arrangement. a

5. A telephone system including subscribers lines, asubscriber-controlled line finding side switchless switch having motionin one plane to select groups of saidq lines and motion in. anotherplane toselect the calling line in the selected vgroup, arelay and amagnet controlling the first'of said motions, a circuit for'said relaycon trolled by said magnet, a circuit for said magnet controlled bysaidrelay, said relay and magnet adapted to energize and de-energizealternately for each selective step of.

. said switch, means for restoring said switch to normal, andmeansincluded 111 a positive drive circuit arrangement for advancingsaid switch in said second plane to permit said switchto restore tonormal. I

6. A telephone system" including. subscribers lines, a line findingswitch having motion in one plane to select groups-of 'said lines andmotion. in another plane to select the calling. line in the selectedgroup,"a

vrelay and a magnet controlling thefirst-of I said motions, a circuitforsaidrlay con: trolled by saldmagnet, and a c1rcu1t for sald" magnetcontrolled by said relay, a relay and a magnet controlling the second ofsaid motions, a circuit for said relay controlled by said magnet, acircuit for said magnet controlled by said relay, and means includingsaid last relay and magnet'for automatically restoring said switch tonormal. '7. A telephone system including subscriberslines, a linefinding swltch having motion in one plane to select groups of said linesand motion in another plane to select the calling line in the selectedgroup, a relay and a magnet controlling the firstof said motions, acircuit for said relay controlled by said magnet, and a 'c-irc'uit forsaidmagnet' controlled by said relay, a (relay and a magnetcontrollingthesecond of said motions, a; circuit for sa1d relay con-'trolled by said magnet, and a circuit for said magnet controlled bysa1d'relay, -and amaster switch'ha'ving' a starting relayforcontrolling. the 1n1t1al energizatlon ofsaidiirst relay.

8. A telephone system including subscribers lines, a line finding switchhaving motion in one plane to select groups of said lines andymotionlinan'otherplane to select a lineinithe selected group, *al test relay,

a driving magnet'a'nd a slow acting relay controlling the first of"said-motions, and-"a m second test relay, [driving magnet andslowactingrelay!controllingwthe second ofsaid motions.

I telephonesystem. including sub-" 4 scrlbers telephone lines, a linefinding-1.

lect g-roups of said lines and motion, in

' another' plane toselect a linein a selected group, a driving'imagnetfor controlling the firstof said. movements, a slow-acting I relay incircuit inffseries withfsaid driving magnet for render ng" lner t sa'iddriv ng magnet andifor rendering 'operat1ve:a-sec 0nd driving magnetcontrolling the second to operate said switchfitopoint -whereitautomatically restores,tojinormali I 10.]A telephone; system. includingsub .ofsaid motions, said secondgniagnetqadapted scrib'ers"telephonefl-ines, line finding.

. switch having motion in "oneplane to, select groups of saidlines andmotionin anotl1er'; plane'to j select {lollIlG m a selectedgroup,

for rendering operative a "second driving:- magnet controll ng thesecond" of-sald mag I nets, and asecond slow act1n'g.;relay{ forrendering inoperative theilseconduof said;

switching operation. I

I A telephone systemincluding -sub' scribers ztelephone lines, .'-alinefinding switch 'having'motion in' one plane to. select groups "of saidlines and motion in driving 'magnets, and for! performing a another.plane tosele'c'tfa' line in-a selected group, a driving magnet forcontrolling the f Ila) firstot said movements, a slow-acting-rel 1 i layfor renderinginertisaid' driving magnet and for rendering operative asecond driving magnet controllingthe 'sec'ond of .said' llU magnets,anda second:slow-actingrelay for A rendering inoperative the second orus'aid driving magnets and} iorperforming switching operation, saidsecond magnet bc-p lng adapted to advance the switch to permit the sameto be restored to'normal.

12.A..te1ephone system including an I automatic non-numerical lsele ctorswitch provided with arswiitch shaft and wipers 12o having movement inone plane to select:

group of lines and movement in a'secondf I I plane' to select a callingline in the-group, a relay and a magnet'ycontrolling the. sec- 'ond ofsaid movements connected:- in a positive sdrive circuit arrangementincluding, contactsof .sald relay and magnet, and a.

slow-acting relay controlling the operation I o-f fsaid jrelay and"magnet andlalso to close contacts'in thei'talki'ng conductors of said)telephoneysystem.

13. A telephone system includin'gean-i automatic non-numerical selectorswitch provided with a switch shaft andwvipers having movement in oneplane 'to select a group of lines and movement in v-a second plane toselect a calling line in the, group, a relay and a magnet controllingthe second of said 'movements connected in a positive drive circuitarrangement, a slow-acting relay controlling the operation of said relayand magnet and also adapted to close-contacts in the talking conductorsof said telephone system, and means for-eausinga second operation ofsaid magnet to advance the switch shaft and wipers to a position wherethey will automatically restore to normal. ll. A-telephone systemincluding anaut-o matic non-numerical selector switch having motion in.oneplane tolselect groups-oi? lines and a motion in a second planetoselect a calling line in the group and to advance the switch to aposition where itwill automaticallyrostore to normal, a relay and amagnet for controlling themoyement o l: the switch in the said secondplane, a circuit for vsaid relay controlledby said mag-i'iet, a circuitfor said magnet controlled by-said -'relay, and a slow-acting relay:Eor'contro lrelay of said master switch and also: for

operating said switch. to connect to one of said groups of. lines.-

16. A telephone system including subscribers telephone lines,- automaticswitches for connecting said lines, a. rotary non-restoring masterswitch for controlling one of said automatic switches, a relay and amagnet for advancing the wipers ofsaid master switch, a circuit forsaid'rrelaycontrolled by saidmagnet, a circuit (for said magnetcontrolled by said relay, said-master.

switchshaft and wipers adapted to always be rotated in the samedirectionand a relay associated with said automatic switch for controlling theinitial energlzatl'on of the relay of .said master switch and also foroperating said switch to. pick out theagroup of lines containing: the.calling subscribers line. 17 A telephone system includingcgroups ofsubscribers telephone lines, automatic and State of switches:fortonnecting said lines a master switch for controlling the initialmovement of one of said automatic switches, a relay and a magnet foradvancing the wipers of said masterswitch, a circuit iorsaid relaycontrolled by said magnet, a circuit for said magnet controlled by saidrelay,- said master switch shaft and wipers adapted to always be rotatedin the same direction, a relay HSSOGRUZGd with said automatlc s-witchfor one of said groups containing the calling line independently of saidmasterswitch after the initia'lsmovement of said automatic switch. a I j18. A telephone system, including subscribers telephone lines, automaticswitches for connecting said. lines, a master switch for controlling theinitial movement of 'one of said automatic switches, ,a relay. and amagnet for advancing athewi-pers of said master switch, acircuit forsaid relay controlled by said magnet, a circuit-for said magnetcontrolled said relay, said master switch shaft and wipers ,adap'tedgtoalways be rotated in the same direction, a relay associated withsaidautomatic switch for controlling-the initial enengization ofmtherelay of said master switch, and a relay common to the subscribers ,forstarting an idle one ot said automatic switches, said second relayoperable vupon the operation ofsaid last v relay fto cause saidautomatic switch to operate to connect: to. agro-up of said linesindependently of said. master switch after the {initial movement of saidautomaticswitch.

. 19.,A; telephone system includingusnb scribers telephone ,:lines, .amasterswitch common to [said telephone lines, a line ,finder switchhaving motion in one plane to select a group of said lines and motionvin {another plane to select a line, in the-selected group, a drivingmagnet fEO1 CO'I1t'1OlllIl g the first of said-movements, a relay. forcontrol ling the circuit of said magnet and .a -circuit for said relaycontrolled bysaid magnet, a irelay associated with said master switchfor initially energizing the relay of said line finderqswitch, andaset'of ottnormal --cont-acts operable I upon ,th e i op eration ofsaidmagnet and relay for effecting the operation of said master switch.

Signed by me at Chicago, county of Cook Illinois this-th day otJune,1919. I

manor 1). KELLOGG.

